where it takes the values stated in (REF ).
This result was conjectured in [1]}, but the proof outlined in that paper
was not mathematically rigorous. Here we complete the proof, combining ideas from [1]} and [3]}. We denote by \(a_i\colon 2\rightarrow 1\) , \(b_i\colon 3\rightarrow 2\)  and \(c_i\colon 1\rightarrow 3\)  the arrows of the quiver.
